Backing up data and restoring it following a software or hardware error constitutes one of the greatest challenges that a company has to face. A malfunction, caused for example by a computer virus, can render an employee's workstation completely unusable and result in considerable losses of time and money. Such outages can be due to a malfunction of a hardware component, such as a hard disk crash, or of a software component, such as the corruption of the operating system or of applications, but they can also be due to involuntary actions and, last but not least, to incompatibilities between newly-installed programs and pre-existing programs.
In some cases, the user is not capable of ascertaining the exact cause of the malfunction and has to execute (or obtain) technical support services for restoring the functionality of the information technology system. The technical support services can take a long time, be complex, costly and in some cases difficult to obtain as well. Often the technical support services are limited to replacing the non-functioning hardware device. In order to render the system operational again, it is necessary to reinstall the operating system and all the programs with their configurations, i.e. the set of customizations that each user makes to his own system in order to improve its usability is not taken into consideration by this process. Normally, hardware technical support is limited to replacing the faulty part, and installation of the operating system and programs is left to the user.
Normal use by a user of an information technology system generally involves the progressive accumulation thereon of data and programs associated with the work activity such as passwords, preferences, settings or combinations thereof. This means that in order to render a compromised system usable once again, it is not sufficient to restore its mere functionality and instead it would be preferable to bring it to the conditions preceding the onset of the malfunction.
The use of “mirroring” based on the use of RAID 1 configurations is effective in the event of breakage of one of the two hard disks, since it comprises two mirror-symmetrical copies. This method however is not suitable in the event of malfunctioning software, such as the involuntary deletion of an important file or the malfunctioning caused for example by a computer virus, which would be mirrored on the other disk. Even RAID 5 systems with multiple disks, which are capable of reconstructing the disk that might fail, are unsuitable when faced with such events, and for this reason such architectures must be supplemented with systems for backing up. Such systems are widely available on the market but they have the disadvantage of requiring intervention by the user, who has to decide when to make a copy to back up the system, where to do it, and what data to save. Similar problems occur if it is desired to migrate from one computer to another one that is considered more efficient, since this operation can require a considerable amount of time.